Analytical methodology for the verification of buried steel pipelines with flexible joints crossing strike-slip faults

The use of "flexible joints" to enhance the performance of buried pipelines at large PGD areas is a novel design approach with promising results. This paper presents an analytical methodology for the preliminary stress-strain analysis of buried steel pipelines with flexible joints crossing strike-slip faults. The analytical predictions are verified against results from parametric numerical analyses performed with a commercial numerical code. The pipeline is simulated with pipe elements following an elastoplastic material law, while the soil is simulated with non-linear winkler springs. The numerical analyses have been performed for a wide variety of PGD magnitudes, fault crossing angles, flexible joint distance and crossing position. For the sake of simplicity, the mathematics of the new methodology and the verification are presented only for joints with rotation capacity. Minor modifications required in order to account for the effect of joint extension are stated in the concluding remarks.